This invention relates to fasteners and is more specifically related to a self-sealing threaded fastener for sealing in cooperation with a complementary receptacle.
It is well known that helical threaded fasteners do not form water-tight engagement with a complementary surface or mating fastener unless a gasket or seal of some sort is supplied between the threaded portion of the fastener and the receptacle or fastener to seal the valleys created by the roots and crests of the threads. Such a gasket is shown in U.S. Pat. No. 2,775,917 issued to W. C. Ferguson on Jan. 1, 1957, which describes a sheet metal nut with an integral gasket that is adapted to flow into and fill the valleys created by the sheet metal thread.
It is also known to provide self-locking fasteners. By nature, such fasteners are not self-sealing. An example of a self-locking fastener is shown in U.S. Pat. No. 3,746,068 issued to Deckert et al on Jul. 17, 1973, which shows an encapsulated adhesive applied directly to the threads of a threaded fastener, wherein said adhesive is pressure actuated as the threaded fastener is turned into a tapped receptacle, for permanently bonding the threaded fastener in the receptacle. Many other similar type devices are known for providing self-locking threaded fasteners such as, by way of example, those shown in U.S. Pat. No. 3,061,455 issued to Anthony on Oct. 30, 1962 and U.S. Pat. No. 3,022,917 issued to Jedlicka on Feb. 20, 1962.
A self-sealing mechanical fastener with a self-contained gasket is shown in U.S. Pat. No. 3,472,301 issued to Pearce on Oct. 14, 1969. As there shown, a flowable sealant is introduced into a cavity provided in the center of the threaded shank of the screw fastener. A plurality of capillaries or channels communicate the sealant cavity with the peripheral threaded area of the shank. The screw fastener is used in typical fashion, and after being secured in a suitable receptacle, a dowel is placed into the sealant filled cavity for forcing the flowable sealant out through the capillaries into the valleys between the roots and crests of the threaded connection to provide for a seal.
The sealing mechanism used with threaded fasteners of the prior art all have the same disadvantage in that each requires a plurality of steps to both secure the fastener in the receptacle and to activate the sealing mechanism. For example, in U.S. Pat. No. 2,775,917 discussed above, the sealing nut must be applied directly to the male threaded fastener either before or after the male threaded fastener is used to secure a plurality of elements to one another. In U.S. Pat. No. 3,472,301, a dowel or similar tool must be used to activate the sealant after the threaded fastener is in place. In addition, the prior art sealing mechanisms are quite costly, and not as reusable as desired. Furthermore, the sealing mechanisms of the prior art do not provide adequate filling and sealing between the two mating fasteners in certain installations.
While the self-locking fasteners are designed to be self-energizing during the normal thread tightening function, the self-locking designs of the prior art are not intended to and do not provide a gasket-type sealing function.